DE1779588C3 - Process for the continuous production of elongated foam bodies with a curved outer surface and device for carrying out the process - Google Patents

Description

The invention relates to a method for continuous Manufacture of elongated, ζ. Β. Foam body of any length with a curved surface, in particular of substantially cylindrical foam bodies made of polyurethane with a large diameter permitting peeling of sheet material, according to the preamble of Claim 1.

The invention also relates to a device for carrying out this method according to the preamble of claim 4.

Such a method and such an apparatus are known from GB-PS 1075605, hereinafter referred to as a partial path of the transport path to which the reaction mixture is applied, initially via a fixed, somewhat sloping support and then into a second transport lane, which in one horizontal or slightly upwardly inclined closed shaping channel is cylindrically deformed, introduced. The web material here is flexible plastic such as polyethylene or kraft paper.

Likewise, a generic method and a generic device are already from the CH-PS 449950 known in which the reaction mixture on serving as a transport path release paper is poured, which in turn from a conveyor line is supported. Details can also be found in the parallel German patent 1504313 of the applicant, to which reference is expressly made.

According to the generic prior art, cylinders of large diameter are made of foamed Made of polyurethane.

For this purpose, the mixed reaction solution is initially slowly and continuously applied to the paper web or the like moved away from the casting station in a slightly sloping path. During this movement In the latter state of the art, the web is divided by conveying devices divided by ri sections supported. It is always reshaped in such a way that it has a hollow shape in the form of a part or whole closed cylinder forms. Along the transport route, which also has a weir behind the loading area the reaction mixture forms, the reaction mixture solution goes through a series of reaction stages, such as setting, thickening, foaming, rising and hardening of the active ingredients, so that finally on delivery end of the shaping channel, in which the transport path in the partially closed cylinder shape is formed, a foam body with a cell-like structure emerges as a manufacturing product, which has the shape of the inside of the shaping channel. The one made in this way Foam body with a curved surface, e.g. B. full cylinder, is then cut into individual sections. These sections are clamped on machines and turned against a knife, which they Peeled off helically in sheet material in the form of long sheets.

Due to the way in which the z. B. fungal growth-like swelling of the active ingredients takes place, the rising foam itself is incapable of wrinkles in the area carrying the foam active ingredients Tape to smooth & n. As a result, the rising foam bridges the spaces between inward-protruding doors of ribbon folds in the Transport path and includes air or gas in these spaces. As a result, cracks, Gas pockets and other faults occur *. These would also be at or near the outer surface of the foamed cylinder or other produced foam bodies and one

"> cause great material wear.

Wrinkles in the belt material of the transport path arise because this is usually made chemically treated removable paper existing tape material of the transport path, which, however, z. B. also from

^{1 (1} polyethylene or the like. Can consist of the feed shaft on which it is wound, peeled off in one direction (e.g. in the longitudinal direction) and then in another direction (e.g. in the transverse direction) to form a curved outline is bent

ι> it may be necessary to use the conveyor belt to bend in different planes at the same time. Because of the limited flexibility and extensibility of the conveyor belt material, these changes in shape often lead to folds, where-

-'Ii by the quality of the to be formed by the transport path Foam body is affected.

The invention is therefore based on the object of the method for producing the foam body and the associated device to be set up

• 2> th, that the foam body produced one Obtain the smoothest possible outer surface, in particular from cracks, gas pockets and other faults is as free as possible, as it was previously due to the formation of folds in the deformed flexible transport path

s "could arise:

A solution to this problem results in the method according to the invention from claims 1 and in the. Device according to the invention from claim 4.

J *> Here the one for the reaction mixture and thus also the transport path that gives shape to the foam body to be produced and aligned so that changes in the shape of the belt material of the transport path are made that tension differences across the width of the strip material are eliminated or kept to a minimum will. This is achieved by guiding the conveyor belt material in such a way that that over the entire otherwise wrinkling

4> the range of the bandwidth of the path for each surface element of the strip material of the web is of the same or almost the same total length, if the transport path from a station with an outline shape of the transport path and thus the reactive

■> <mix of ions to a station with a new outline shape wanders.

In order then to ensure that the conveying path, guided in this way essentially free of creases, does not result the previously mentioned lack of support

> -> not solidified reaction mixture inside can buckle, which in the case of pure external guidance in the shaping channel again lead to folds would, especially if the edges of the strip material of the transport path inevitably to upwards

ho soaring side walls of substantial height reshaped the bulged web is also guided inside until the reaction mixture solidifies takes over the inner support. For this, see the device according to the invention a support

h ") body within the shaping channel in order to in this way to delimit a guide gap for the transport path between the two supports through the shaping channel and support body, through the

the track can run without kinking. The special inner support can be designed so that its increasing Lower edges reach straight down to the expanding foam rising upwards. on in this way the web rests along the entire shaping channel partly on the inside Foam, tiels on the support body, preferably the transition of the independent of the reaction mixture Support of the web on the foaming reaction mixture just above the level the same is made.

During the foaming of the reaction mixture, it is expedient to use one on both sides of the reaction mixture the supporting web synchronously moving separate Supporting surface formed, each of which the reaction mixture against the edge zone of the supporting Shields the web in an overlapping manner.

A device suitable for this purpose, optionally in the embodiment according to claim 9, is shown in claim 8. If a leadership of the partial webs is made according to claim 10, the lateral partial webs are guided lengthways in a simple arched contour shape, while the bottom-forming c middle partial web when transferring from the task area via an entrance guide, z. B. a Weir and during the final shaping of the web in the shaping channel changes in its outline shape learns. Because of this change in shape, in the transverse direction, the edges of the central partial web, which give way has a constant width, back and extend laterally upwards when the middle partial web moved lengthways. The independent lateral partial webs, however, are affected by the changes in shape that the Lateral orientation of the edges of the central partial web determined, not influenced. The lateral movements the rounder of the middle partial web are therefore easily picked up so that no creases arise because the overlapping edges of the partial tracks slide easily on top of each other.

Further advantageous embodiments of the invention ^:

In the device according to FIGS. 1 and 2, an active ingredient solution 10, as it is, for. B. in U.S. Pat 3281894 and 3296685 is described, through a nozzle 12 onto the application surface of a supporting surface 14 poured and conveyed on with this, the active ingredients enter into a reaction and an elongated one Form foam body 16 with a cellular structure. The surface 14 is from a transport path 18 formed from paper web or paper tape material. The track 18 is made up of partial tracks, namely one middle bottom band 18a and two side bands 18b and 18c, together. All partial taps can be turned off Paper exist and are provided with a coating, which after completion of the forming activity Removal of the foam body produced allowed.

The bottom belt 18e is driven by a supply roll (not shown) by means of a Pinch roller pair 20 withdrawn. The partial webs run through a gate 22 and under the nozzle 12 here. The gate 22 is a structure used to accommodate the nozzle 12 and the various piping and to carry other supply lines. The web moves from the nozzle through an entry guide 23 and via a weir construction 24.

The i'-shaping channel 26 is composed of one middle, a floor belt presenting belt conveyor 28 for the middle partial web 18c (FIG. 1) and a pair of laterally arranged belt conveyors 30 together. The middle belt conveyor 28 is flat and provides the floor support in the forming channel 26. The side conveyors 30, as shown in FIG A plurality of abutting support members 32 designed as shaped segments, which cooperate form a continuous support for the web 18. As can be seen from Figs. 4 and 5, the Support members 32 are shaped on their support surface as an arch of a cylinder, which form the shaping channel 26 limit. All conveyors 28 and 30 are by means of

Proverbs 5 to 7.

The invention is illustrated below with reference to schematic drawings of an exemplary embodiment explained in more detail. It shows

Fig. 1 is a partially sectioned view of the main part: 5 of a device for continuous Manufacture of elongated foam bodies with a curved outer surface from a freely foaming one Reaction mixture,

FIG. 2 is a side view, also partially in section, of the device according to FIG. 1,

FIG. 3 shows an enlarged partial view of part of the device according to FIG. 2,

FIG. 4 shows an enlarged view of a section along the line 4-4 in FIG. 2,

FIG. 5 shows an enlarged view of a section along the line 5-5 in FIG. 2,

6 shows a perspective partial view of the input part of the device according to the preceding figures,

FIG. 7 is a perspective view of a weir design used in the device according to FIG Figs. 1 to 6, and

8 A, B and 9 A, B Graphical illustrations of method features for avoidance formation of creases in the transport path through appropriate path guidance.

chronologically driven, so that the shaping channel 26, which forms a mold bed, moves continuously away from the nozzle 12 in the direction of arrow A.

Near the front end of the conveyor assembly 28. A stationary support body 36, which forms an inner shape for the web 18, is provided. This has a general tubular shape and, as can be seen in FIG. 4, lies tightly from the inside to the circular cylinder limited by the cooperating support members 32.

From Fig. 3 it can be seen that the support body 36 extends only a short distance backwards than over its circumference full of cylinders and then trimmed in this way is that it is sloping towards the top, and at first quite steep, as indicated by 38, and then flatter as indicated by 40. The upper inner portion of the support body 36 is stiffened by a strut 42. A (not shown) Arrangement is provided to support the support body above and in a fixed position to the different conveyors 28 and 30 to keep.

The weir 24 shown in FIGS. 3, 7 and 8 can be designed as a sheet metal construction. How to can be seen, it is raised in front of the shaping channel 26 to a part of the reaction mixture solution to be retained until gel formation begins.

In Fig. 6 it can be seen that the upstream

7 79 588

send end of the support body 36 engages over the weir 24. The middle partial web 18a brushes over the Weir 24 away. This situation is shown in FIG. 6, in which it can be seen how the middle partial web 18a is guided over the weir and into the support body 36 bhein. The middle partial web 18a is considerably wider than the design of the weir 24 itself. Accordingly, the edges of the central one Partial web 18a bent upwards in order to introduce the middle partial web into support body 36. this will accomplished by the entrance guide 23. This has according to the drawing on the side Guide walls 56 and 58, which protrude upwards in front of and on both sides of the weir 24. This lateral Guide walls form a distinct slide, which the middle partial track 18a during their movement over the weir 24 gives a special shape.

In Fig. 7 it can be seen that the slide formed by the guide walls 56 and 58 is initially trapezoidal Has cross-sectional shape, which then tapers inwardly downstream, and that the guide walls 56 have a greater height to the constant width of the central partial web 18a balance.

In the vicinity of the weir 24, the straight guide walls 56 merge into the curved guide walls 58. In addition, as can be seen in FIG. 6, the guide walls 58, seen downstream, go outwards apart to finally converge with the curved surface of the support body 36.

According to FIGS. 1, 2 and 6, the lateral, outwardly arranged partial webs 186 and 18c of lateral supply rolls 60 arranged vertically with their shafts are withdrawn. The ligaments of the lateral Partial webs 186 and 18c each run around an assigned guide roller 62. The guide rollers are slightly inclined to change the direction of travel of the webs so that they are towards the sides of the Forming channel 26 run parallel and in alignment with them.

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mc in ι i

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Chen partial webs 186 and 18c on the outside of the guide walls 56 and 58, the weir 24 and on the Outside of the inner support body 36 along. However, as shown in Fig. 4, they go through circular arc-shaped, of the support body 36 and the support members 32 of the lateral conveyor 30 of the shaping channel 26 limited column. This process causes both surfaces of the lateral partial webs 186 and 18c and thus prevents the formation of wrinkles. Behind the inlet end of the Support body 36, at the point where this is sloping upwards, come the lower edges of the lateral Partial webs 186 and 18c with the edges of the running on the ground middle partial web 18a in overlapping contact and thus form the complete composite sheet 18 for shaping and supporting the reactive mixture solution.

1 and 2, the nip rollers 20 for the middle partial web and the supply rollers 60 for the lateral partial tracks are driven synchronously with the conveyors 28 and 30. This is to keep the uniform Movement of the three partial webs 18a, 18 6 and 18 c to maintain and a relative movement between the belts of track 18 and conveyors 28 and 30. That way it becomes The occurrence of tensions and the resulting wrinkling in the partial webs are avoided.

When the device is in operation, the middle belt conveyor 28, which runs on the floor, and the side belt conveyors Belt conveyor 30 and the nip rollers 20 used to pull off the middle partial web 18a and the supply rolls 60 of the lateral partial webs all by the synchronizing drive 34 operated synchronously. Then the reaction mixture solution 16 is poured from the nozzle 12 onto the floor belt 18a. The liquid flows down to the weir structure 24 and into the reservoir 68. Then it penetrates over the weir and continues downward through the forming bed 26.

The first part of the rising foam is bound by the bottom-forming middle partial web 18a. Eventually the foam grows beyond their side walls, and now mainly take over the lateral partial webs 186 and 18c the lateral delimitation of the foam.

The side sub-webs 186 and 18c are initially on both sides on the one hand by the support members 32 of the shaping channel 26 and on the other hand by the support member 36 arranged therein, as shown in FIG. 4, supported as a whole. Where the Foam rises, as FIG. 3 shows, the support member 36 is beveled upwards, away from the foam. Of the Part of the lateral partial webs now coming free from the upwardly sloping inner support member 186 and 18c is taken up at the same time by the rising foam itself, which forms the partial webs presses outward against the support members 32 before the bands of the partial webs under their own weight can buckle and form folds.

It can be seen that as a result of the various changes in shape which the central partial web 18a when driving over the weir 24 and introducing it into the shaping channel 26, the edges of the Step 18 one after the other in the lateral direction and step back. That sideways movement the web 18 is due to the overlapping arrangement of the lateral partial webs 186 and 18c and the am

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recorded. The lateral partial webs 186 and 18c can thus with a continuously curved Outline shape and progress without lateral movement of the edges, while the lateral movement of the Edges of the middle partial web by a more or less extensive overlapping of the adjacent ones Tapes 18a, 186 and 18c is caught. This way the difficulties of transferring lateral movements of the edges around almost the entire circumference of the shaping channel 26 around and prevents the formation of creases in the web that this causes.

FIGS. 8 A / B and 9 A / B explain the mode of operation of the device by means of which the formation of wrinkles in the web 18 is reduced or entirely prevented during the change in the shape of the band contour. As shown in Fig. 8A, a conventionally guided belt 80 moves between two parallel planes I and II, changing its shape from a flat to a curved contour shape. The plane I is defined by right-angled coordinates X ₁ and Y ₁ , the plane II by corresponding right-angled coordinates X _n and Y ₁₁ . The movement path of the belt along a plane IN is marked by a line Z between the planes I and II and the coordinates X _n and Y ₁₁ .

As the belt moves forward, they bend

its edges 82 and 84 upwardly and inwardly into a curved shape, while the centerline 86 of the belt moves along the middle of plane III.

It can now be clearly seen from FIG. 8B that the band reaches plane II with the band center 86 in front of the band edges 82 and 84. The consequence of this is that the band edges 82 and 84, as indicated by the arrows 82a and 84ο, diverge continuously upwards. In order to ensure that the tape advances along plane III and that the tape edges follow paths parallel to this plane, as indicated by the dashed arrows, the tape edges must be stretched by an amount Λ Z so that the tape with the entire cross-section is simultaneously in Level II enters. However, this results in unequal tension ratios across the bandwidth, so that the oäiiu ii'i ucf miiiciZOnC is tensionSirCi, against which there are considerable tensions at the edges, with the result that wrinkles can form as a result of this unequal tension distribution. Fig. 9 explains the guidance of the tape according to the method according to the invention. Instead of changing its shape in level III, the band is forced to start at a distance Y _(i) above level III and at the same time to run back into this level, changing the band shape. In this process, the belt enters both plane III and plane II at the same time as the belt center 86. With this arrangement, as shown in Fig. 9B, the tape reaches plane II with the edges 82 and 84 at the same time, so that the continuous path of movement of the tape for the lines 82, 84 and 86 in the direction of the parallel arrows 82b, 84f »and 86a.

The distance Y ₍₁₎ is chosen so that the movement

Movement path of each belt element over the belt width from level I to level II has essentially the same length. Any known geometrical method can be used to determine the distance Y _(l) , but it should be noted that the edges 82 and 84 are subject to displacements in both the ^ -direction and the Y-direction. The above regularities also apply in connection with the change in the shape of the bottom-forming middle partial web 18a, if it sweeps over elevations of different heights, such as the weir. As can be seen in Figures 8A / B and 9 A / B, the path of travel of the belt must change in order that the moving belt can be subjected to changes in shape without wrinkles. This means that where the edges of the tape converge inward in the .Y-direction, the tape in the center line must change its trajectory in the Y-direction. This change in the tape movement in the Y direction of the central partial web 18a now takes place when the weir 24 is driven over. To prevent creasing, the movement path of the edges of the central partial web 18a must be changed in the "direction, ie the central partial web must be inwardly This taper is caused by the inlet chute walls 56 and 58 as seen in Figures 6 and 7. As before, the amount of taper is so

ι to choose that it is guaranteed that the movement path for each point of the path cross-section as far as possible has the same length. If so, different tensions are kept to a minimum and will wrinkle the

i the band of the middle partial web 18a avoided.

In addition 5 sheets of drawings

Claims (10)

Patent claims: 1. A process for the continuous production of elongated, z. B. Any length, foam body with a curved outer surface, in particular of substantially cylindrical foam bodies made of polyurethane with a large diameter allowing sheet material to be peeled off from a liquid reaction mixture by placing the same on a flexible transport path and by supporting the on this path further moved reaction mixture along a until the end of the foam expansion Reaching reaction path by means of the flexible web under its externally guided bulge in a shell, whose Inner surface forms the foam body and the last part of the reaction path through the solidifying reaction genius from within is supported, characterized in that a relative The arched web areas remain at least partially due to the lowering of the web is compensated, and that the arched web is also guided inside until the solidifies Reaction mixture takes over the inner support. 2. The method according to claim 1, characterized in that the transition from the reaction mixture independent support of the web on the foaming reactant mixture in each case is made just above the mirror of the same. 3. The method according to claim 1 or 2, characterized in that during the foaming of the reaction mixture this moved on both sides by one in each case synchronously with the supporting track separate support surface is formed, each soft the reaction mixture against the Shields the edge zone of the supporting web in an overlapping manner. 4. Apparatus for carrying out the method according to any one of claims 1 to 3 with a feed nozzle for applying a liquid reaction mixture to a flexible web of an inlet guide of the web arranged below the feed nozzle and extending in the conveying direction for deforming its cross section, a slightly inclined to the horizontal Shaping channel for the reaction mixture, through which the web is guided, and an external guide for the web in the shaping channel, which arches the web into an outer shape of the foaming reaction mixture, the inner surface of which is complementary to the curved surface of the foamed foam body, characterized in that between the inlet and The output of the input guide (23) is the same as the conveying path traversed by each cross-sectional point of the web, and that a support body (36) is arranged within the shaping channel (26) which, with the inner surface of the shaping channel, forms a guide gap for the web n (18, 18a, b, c) , extends close to the entrance area of the shaping channel from above almost over the entire inner circumference of the same and in the direction of the end of the guide approximately channel has a taper, the bottom (40) extends slightly above the level of the foaming reaction mixture. 5. Apparatus according to claim 4, characterized in that the shaping channel (26) is formed by a conveyor arrangement (28, 30) having a plurality of conveyors (30), one of which each contributing with support members (32) to the shaping surface of the shaping channel that the support members (32) form a substantially cylindrical shaping surface, and that at least the boundary surface of the guide gap on the support body in the conveying direction (36) has a cylindrical shape. 6. Apparatus according to claim 4 or 5, in which the application area of the reaction mixture is easy is arranged sloping, characterized in that the slight inclination of the shaping channel (26) is also sloping. 7. Device according to one of claims 4 to 6, in which the input guide of the web below the feed nozzle has a flat feed surface that is inclined downwards in the conveying direction, which is provided with upright lateral boundary walls, characterized in that a upwardly inclined weir (24) sloping down towards the foaming surface in the conveying direction behind the feed nozzle (12) it is provided that the incline extends from the end of the feed surface of the - preferably arranged in the middle of the system - weir (24) in the vicinity of the the area of the entrance guide that deforms the web cross-section rises, and that the upright lateral boundary walls (56) of the task area as upright lateral boundary walls (58) of the weir to continue. 8. Device according to one of claims 4 to 7 with several complementary in the Formgebmgskanal Partial webs, one of which is centrally from below the feed nozzle (12) via the inlet guide and runs along the bottom area in the shaping channel and joins the two Lateral surfaces in the shaping channel overlap with the partial web material there, characterized in that that the web has three partial webs (18a, 18b, 18c) which complement each other in the transverse direction in the shaping channel (26), of which the two outer / partial tracks (18fc, 18c) each lengthways one of the two side surfaces in the shaping channel. 9. Apparatus according to claim 8 with synchronous feed speed of the partial webs, thereby characterized in that the drive of the three partial tracks (18a, 186,18c) with the drive of the Conveyor arrangement (28,30) is synchronized (by 54). 10. Device according to one of claims 7 to 9, characterized in that the middle Partial track (18a) over the weir (24) between the lateral boundary walls (56) of the entrance guide (23) is guided, while the two outer partial webs (18b, 18c) outside of this lateral boundary walls (56) are guided outside the entrance guide (23).